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Porovnání mléčné užitkovosti genotypů českého strakatého a holštýnského skotu chovaných ve stejných podmínkách
NOVÁKOVÁ, Hana
The basic prerequisite to the economic prosperity of an agricultural company specializing in dairy cows is maximum production of milk and, by extension, dairy by-products at minimal production costs. In order to achieve that it is necessary to have dairy cows with the potential to reach optimal dairy production in the conditions of the given agricultural company. The objective of this paper is to assess the effect of genotype, lactation sequence, and age of the dairy cow at first calving on the parameters of her milk productivity. Our monitoring was conducted at a company named CIZ-AGRO, a. s., Cizkrajov. For our analysis, we used productivity data measured from October 2012 to February 2015, during which the cows ended at least one lactation period lasting 240 305 days. These input parameters were collected from a total of 495 dairy cows that had ended a total of 997 lactations. The compilation of lactations was subsequently sorted out by genotype and lactation sequence, and thereupon by genotype and age of the dairy cows at first calving. Thus classified groups were assessed by average milk production, dairy fat, milk protein per lactation, and percentage content of fat and protein in their milk. The obtained results were thereupon subjected to a statistical analysis. The highest average milk productivity per lactation (9283 liters) was achieved by dairy cows in the group H100 that calved first at the age of over 27 months; the lowest milk (6239.2 liters) was recorded with a C100 heifer. In the group classified by lactation sequence, the differences were not statistically significant, the groups classified by the age at first calving, the differences were less significant statistically (P<0.05). Evaluation of the percentage content of milk components as well as the overall production of milk components per lactation in the group of lactations classified by genotype and lactation sequence, there were no statistically significant differences between the individual groups identified. In the group of lactations classified by genotype and age at first calving, the result showed less significant differences (P<0.05) between the group evaluated by total milk fat productivity and milk protein content per lactation. Monitoring the percentage content of fat in the milk in relation to the genotype and age of the dairy cow at first calving recorded medium level of statistically significant differences between the groups (P<0.01).
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Evaluation milk yield and fertility cows in drove of Bohemian Spotted cattle
ZADÁKOVÁ, Martina
The aim of this work was evaluation of milk yield and fertility of cows´ groups, which were formed on the basis of milk production quantity, age, a calving season, pedigree, body framework of cattle and a level of body condition. There were evaluated results at 690 cows in years from 2004 to 2007. The foundation dates about the yield and the fertility of animals were abtoined by check of the yield. The body framework of cattle and condition were investigated with regular month intervals during the year 2007. Body condition was considered in an interval from 1 to 5 points with accuracy of 0,25 point. During the watching years milk yield increased from 6 616 kg to 8 507 kg. Milk components reduced with increasing milk yield, when the contents of fat was gradually reduced from initial 4,2 % to 3,87 %. The contens of proteins was also reduced from 3,5 % to 3,37 %. It was investigated that the decline of body condition after calving was connected with extension of insemination interval and service period by six days and its increase with shortening of interval and SP by four days. The higher milk yield (8 281 kg) but at the same time longer service period was investigated with cows of bigger body framework (the hight in back from 145 to 150 cm). During the evaluation of effect breeding groups (C1, C2, C3) to fertility weren´t investigated more important differences among the groups. But the breeding groups influence the hight of milk yield, ehen the C3 group (share of dairy breed more than 50 %) has the highest milk yield (7 866 kg). The highest milk yield was investigated with cows at the second lactation period (7 900 kg), at the third lactation period was almost on the same level (7 886 kg)and in the following lactation periods the quantity of milk gradually fell down. The examination of lactation curve courses at cows´ group with a different level of yield indicated , thet the higher care in a herd is devoted to milk production than to cows´ fertility. The length of service period at the highyield cows was as 200 days.
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